Dual-path optical system

Abstract

Pseudoscopic, dual-path optical systems employing plane mirror arrangements for cross coupling the optical paths to reverse the left and right perspectives of object space are provided. Advantageously, the cross coupled path arrangements permit the systems to be manufactured inexpensively because low-cost reflective components can be used and assembled with alignment requirements that are significantly relaxed compared with customary requirements found in uncoupled systems utilizing high-cost prisms or mirror arrangements for similar purposes.

What is claimed is: 
     
       1. A dual-path, pseudoscopic optical system comprising: a pair of objectives arranged along separate optical axes that are spaced apart from one another by a predetermined distance;   a ninety-degree roof mirror system comprising upper and lower plane mirrors intersecting one another along a line substantially parallel to both optical axes of said objectives;   a pair of crossed plane mirrors arranged one above the other in planes that intersect one another approximately at a right angle, one of said crossed plane mirrors being positioned to intersect said optical axes of said objectives to fold them so that light rays travel to said upper mirror of said roof mirror system from which they are reflected to travel downwardly to said lower mirror of said roof mirror system after which they are folded again by said lower mirror of said roof mirror system to travel along a direction opposite to the one in which they entered said roof mirror system and offset with respect thereto, the other of said crossed plane mirrors being arranged to intercept rays reflected from said lower mirror of said plane mirror roof system and direct them rearwardly along two separate optical axes that are parallel to said optical axes of said objectives, vertically offset with respect thereto, but spaced apart by said predetermined distance by which said objective optical axes are spaced apart, said objectives, said roof mirror system, and said plane crossed mirrors being arranged to form pseudoscopic real images of an object space along said rearwardly extending optical axes; and   a pair of eyepieces arranged, respectively, along said rearwardly extending optical axes for observing said pseudoscopic images.   
     
     
       2. The optical system of claim 1 further including means for adjusting an interpupillary distance between said eyepieces. 
     
     
       3. A pseudoscopic binocular system comprising: a housing;   a pair of objectives located in said housing and arranged along separate optical axes that are spaced apart from one another by a predetermined distance;   a ninety-degree roof mirror system arranged in said housing and comprising upper and lower plane mirrors intersecting one another along a line substantially parallel to both optical axes of said objectives;   a pair of crossed plane mirrors fixed in said housing and arranged one above the other in planes that intersect one another at approximately a right angle, one of said crossed plane mirrors being positioned to intersect said optical axes of said objectives to fold them so that light rays travel to said upper mirror of said roof mirror system from which they are reflected to travel downwardly to said lower mirror of said roof mirror system after which they are folded again by said lower mirror of said roof mirror system to travel along a direction opposite to the one in which they entered said roof mirror system and offset with respect thereto, the other of said crossed plane mirrors being arranged to intercept rays reflected from said lower mirror of said plane mirror roof system and direct them rearwardly along two separate optical axes that are parallel to said optical axes of said objectives, vertically offset with respect thereto, but spaced apart by said predetermined distance by which said objective optical axes are spaced apart, said objectives, said roof mirror system, and said plane crossed mirrors being arranged to form pseudoscopic real images of an object space along said rearwardly extending optical axes; and   a pair of eyepieces fixed in said housing and arranged, respectively, along said rearwardly extending optical axes for observing said pseudoscopic images.   
     
     
       4. The binocular system of claim 3 wherein said roof mirror system is moveable in said housing to focus said binocular system. 
     
     
       5. The binocular system of claim 3 wherein said roof mirror system is moveable in said housing by means of a mechanical slide arrangement.. 
     
     
       6. The binocular system of claim 3 further including means for adjusting an interpupillary distance between said eyepieces. 
     
     
       7. The binocular system of claim 6 wherein said means for adjusting the interpupillary distance between said eyepieces is structured and arranged to move one of said eyepieces and one of said objectives in equal and opposite directions while keeping the other of said eyepieces and said objectives stationary. 
     
     
       8. The binocular system of claim 3 wherein each of said objectives comprises a single element positive dioptric power lens. 
     
     
       9. The binocular system of claim 3 wherein said roof mirror system and said crossed plane mirrors are each mounted so that they are mechanically isolated from movement in said housing. 
     
     
       10. The binocular system of claim 3 wherein said eyepieces are in the form of modified Ramsden eyepieces.